Since Vim uses nearly the entire keyboard to do different things depending on the mode it is in, simple typos can have much bigger effects than in most other editors. A one-letter difference can make Vim do something entirely different than what you intended. While it is normally easy enough to just undo the mistake, it can be better to avoid the mistake entirely.

Normal and insert modes

If you find yourself making a typo very frequently in a normal-mode command, and accidentally enter a command you almost never use, it is very easy to correct.

For example, if in insert mode you often miss the <Esc> key and hit <F1> instead, you can map <F1> to either a "do nothing" command, or to the intended <Esc> command:

inoremap <F1> <Nop>

inoremap <F1> <ESC>

If in visual or normal mode you accidentally hold down the <Shift> key while pressing the <Down> arrow, and you only intend to press <Down> and not <S-Down>: